CSU Scientific Conference

贪心：

#include<stdio.h>

#include<stdlib.h>

#define MAXN 100000 + 100



int Ts[MAXN], Te[MAXN], r[MAXN], n, num;



int cmp(const void *_p, const void *_q)

{

    int *p = (int *)_p;

    int *q = (int *)_q;

    return Te[*p] - Te[*q];

}



void init()

{

    while(~scanf("%d",&n))

    {

        for(int i = 0; i < n; i ++)

        {

            scanf("%d%d",&Ts[i],&Te[i]);

            r[i] = i;

        }

        qsort(r,n,sizeof(r[0]),cmp);

        num = 1;

        int t = 0;

        for(int i = 1; i < n; i ++)

        {

            if(Ts[r[i]]>Te[r[t]]) 

            {

                num ++;

                t = i;

            }

        }

        printf("%d\n",num);

    }

}

int main()

{

    init();

    return 0;

}